During the manufacture of metal strip material, it is often necessary to pay out strip material which has previously been wound into a coil so that the strip material can be further processed such as by passing it, while cold, through the rolls of a rolling mill. Apparatus has been developed for positioning the coil of strip material and for feeding it automatically into the further processing station, which is usually the gap between the rolls of a rolling mill. It is necessary, however, that the coil should be positioned relative to the apparatus for feeding it into the processing station so that the end of the outer turn of the coil is in a predetermined position. To this end it is necessary to detect the position of the end of the outer turn of the coil with a considerable degree of accuracy.